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Nails/Transcript
Transcript Text Reads: The Mysteries of Life with Tim & Moby Tim reads from a typed letter. TIM: Dear Tim & Moby, how do nails grow? From, Allison. Mine hardly seem to grow at all. Maybe I should stop biting them. Tim looks at his fingernails. TIM: Nails are part of the integumentary system, along with hair and skin. The integumentary system is in charge of protecting your body. So biting your nails is a bad idea, since nails are there to protect your fingers and toes from damage. An image shows Tim's fingernails, hair, and teeth. TIM: Nails also allow you to pick up objects as small as a grain of sand and open soda cans and stuff. An animation shows fingernails picking up a grain of sand and Tim opening a can of soda. TIM: This is gonna sound weird, but nails are actually made of keratin, the same protein that makes up your hair. An animation shows fingernails combing through a head of hair. TIM: Nail cells that you see are dead. Just like hair. An image shows a close up of a fingernail. A tombstone saying R.I.P. appears on top of the fingernail. TIM: The only live cells are found at the growing points. Here’s how nails grow. The matrix is the part of the nail that makes new cells. An image shows a close up of a nail, then a side view of the inside of the finger, revealing the bones and tissues underneath the skin. A label shows that the matrix is located just beyond the base of the nail. TIM: The matrix adds cells to the base of the nail root. To make room for these new cells, the nail plate slides over the nail bed and your nail grows longer. An animation shows the nail matrix adding multiple rows of cells. The image of the finger reappears and labels indicate the nail bed (the area beneath the nail) and the nail plate (the top of the nail). The nail plate grows and extends beyond the tip of the finger. TIM: Each fingernail grows about two to four centimeters each year. Toenails grow slower, just a couple of centimeters each year, give or take a centimeter depending on the case. Moby shows his finger to Tim. TIM: Ooh, a hangnail! Hangnails and tears in your nail can be really painful. So if you're active, it's a good idea to keep your nails short. Tim holds up a picture of a painful, cracked nail. It looks red and inflamed. TIM: Just like hair, everyone's nails may grow at different speeds. Your best friend's nails may naturally grow to a longer length than yours. An animation shows eight different hands. Moby tries to scratch his own back. TIM: Sure! Nails are also good for scratching your friend's back. Tim scratches Moby's back several times before stopping and frowning. TIM: Wait a second, you don't have nails. How can you have a hangnail? Category:BrainPOP Transcripts